title: Electronic structure of Eu-C(70) fullerides.
abstract: The electronic structure of Eu-intercalated C(70) has been studied by a synchrotron radiation photoemission spectroscopy technique. At low intercalation levels (below the stoichiometry of Eu(3)C(70)), the photoemission data clearly exhibit charge transfer from Eu 6s states to the lowest-unoccupied-molecular-orbital (LUMO) and the LUMO + 1 of C(70). The amount of charge transfer reaches its maximum far before intercalation saturation. Detailed analysis reveals that most of the 5d6s electrons of Eu occupy the so-called interstitial states in the saturation phase (Eu(9)C(70)). The interstitial states are induced by a Eu sub-lattice formed at heavy intercalation levels, and comprise substantial 6s-π hybridized states. The π states participating in the hybridization are mainly the HOMO - n (n = 6-10) orbitals. The PES data also reveal the semiconducting property for both Eu(3)C(70) and Eu(9)C(70). The 6s-(HOMO - n) hybridization and the semiconducting property should play important roles in understanding the ferromagnetic mechanism for Eu(9)C(70).
authors.affiliation: Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Liang
authors.initials: L
authors.lastname: Meng
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Wang
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Li
authors.forename: Chun-Qi
authors.initials: CQ
authors.lastname: Sheng
authors.forename: Wen-Hua
authors.initials: WH
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Xu
authors.forename: Fa-Qiang
authors.initials: FQ
authors.lastname: Xu
authors.forename: Jun-Fa
authors.initials: JF
authors.lastname: Zhu
authors.forename: Hong-Nian
authors.initials: HN
authors.lastname: Li